Abundance and first record of benthic macroinvertebrates in Lake Metztitlan, Hidalgo, Mexico

Resumo

Lake Metztitlan is an endorreic lake with changes in its water levels which is now confined to approximately 650 ha. These changes are a consequence of anthropogenic factors such as the use valleys soils for intensive agriculture. Therefore, in this study it was considered relevant to know the macrobenthos of this lake due to the importance of the use of benthic organisms as indicators to characterize an aquatic system. This is the first registration for Metztitlan lake. Samples were taken bimonthly with a Van Veen dredge and a mud sifted with a light of mesh of 1 . Three hundred and sixty two organisms were identified and placed into two phyla (Annelida and Arthropoda), from the most to the least abundant, the following benthic organisms were present: Lumbriculus variegatus, Cypris sp., Chironomus sp., Tanypus sp., Helobdella elongata and Procladius (Holotanipus). An increase in the abundance and number of species were observed in May and July, time in which the minimum levels of water and maximum levels of temperature occurred. The family Chironomidae was the most represented with 50% of the genus. We could say that the low abundance of Chironomids in this reservoir may be a response to the use of insecticides on the adjacent crops as well as to the predation caused by the fishes that occur in this lake (tilapia and carp species).